Station selection



March 28, 1939. I w, J ZENNER STATION SELECTION Filed Dec. 24, 1956 INVENTOR. WALTER J. ZENNER Patented Mar. 1939 PATENT OFFICE v 2,152,010 STATION SELECTION Walter J. Zenner, Des Plaines, Ill., assignor to Teletype Corporation, Chicago, 111., a corporation of Delaware Application December 24, 1936, Serial No. 117,533

2'1 Claims.

The present invention pertains to telegraphic communication systems and more particularly to telegraph systems involving a plurality of stations arranged with instrumentalities for their selective interconnection for telegraphic communication.

An object of the invention is the provision of simple and reliable circuits and mechanisms to enable any station of a telegraph system to select another station or a group of stations with which it is desired to communicate.

An object also is to provide a system of answerback communication such that when a station has responded to its calling code signal, a response signal or answer-back signal comprising character-code signals will be transmitted automatically over the interconnecting line circuit.

A further object is to enable the originating station after selecting tions to establish a condition by which all other 20 stations of the system are prevented from interrupting the established communication, except that a preferred station may be equipped to monitor a message and to interrupt transmission of the message if desired.

According to the foregoing answer-back system, it is necessary to prevent a reflective response arising from transmission of an answerback signal and to this end it is a feature of this.

invention so to assign selective codes for calling signals and for answer-back signals that no answer-back signal will duplicate any calling signal,

not even the calling code signal of its own station.-

Further features of the invention reside in the provision of means to manifest prominently at all times the communicative or idle condition of the line circuit as well as the communicative or idle condition of the station apparatus, and recordat all stations the station-selective details of communications which have been established m upona transmission line as well as all selective details of a currently existing connective condition, to' provide a break signal will not conflict with code-signal conditions nor with motor control signal conditions, to prevent 5 inadvertent operation of breaking or motor controlling keys at a station currently excluded from an established communicative condition of the line circuit, and to provide means for a monitoring station whereby an operator thereat may in- 50 clude the station apparatus efiectively in the communicative condition of the line when so desired. I

The above and other objects of invention are attained by utilizing a plurality of printing tele- 55 graph sets, each having as a part thereof a motor a desired station or sta' condition which driven selector and a driving motor therefor, to which keys, relays, and visual signals are added at each station to efiect a method of operation according to the present invention; namely, that an operator at one station may start all motors 5 to drive all selectors,'then by utilizing the printing selector in concomitant function of astation selector may indicate and modify all desired sta-, tions for communication, then may disqualify all non-indicated and non-modified stations by 'stop- 10 ping their motors or otherwise, after which the indicated stations may intercommunicate between or among those stations exclusively.

A more complete understanding of the invention will be obtained by the following description, taken in connection with the accompanying drawing wherein;

Fig. 1 shows a line circuit and circuits of three sub-stations,

Fig. 2 shows a detail of keyboard operating 5 mechanism utilized in the answer-back system, and

Fig. 3 shows a detail of selector mechanism utilized in station selection and associated control functions.

Referring first to the mechanical detail illustrated in Fig. 2, a common operating bail I extends across all of the key levers 2 of a telegraphic transmitting keyboard, at a sufiicient height above the key levers to approach them but not to engage them. Upon a desired key lever 3, a striker 4 is clamped having a lugtherepn in position to be engaged by bail l when it" is rotated upon its axis 5 in response to energizing of an answer-back magnet 6, thus effecting mechanical operation of a predetermined key lever.

Referring to Fig. 3 the mechanism illustrated therein is excerpted from the disclosure of Patent 1,904,164 issued to S. Morton et al., specifically Fig. 2'7 thereof. code signal member II is tensioned by spring l2 and is restrained by an operating bail l3. Six rocking vanes M are positioned to obstruct the rotation of member ll upon its pivot [5 when any vane is in as determined by the location of notches in the code-signal member II. An electrical contact spring I6 is moved by member II when operated, and a switching function is performed among contacts of spring l6 and contacts of its asso- 50 ciated fixed contact members l1.

In each station equipment there areincluded two manual keys l8 and IQ of dashpot type adjusted for different time periods in operation. In each key, depression of the operating knob trans 55 In Fig. 3, an operating other than its code-signal position mits mechanical energy through the electrical contact members to the plunger of the dashpot and moves the plunger accordingly while retaining closed the electrical circuit of the key. Upon manual release of the key, the upper contact member returns at once to mechanical normalcy thus opening the electrical the lower member of the key begins its return movement, restrained by the dashpot, and subsequently closes the electrical circuit of the key after a time period .determined by preliminary adjustment of the dashpot elements. Key I8 is adjusted to hold line circuit 3| open for a time period suiiicient to deenergize all slow-to-release relays 36 and to permitrelease 03? their armatures, while key I8 is adjusted for a time period longer than a code signal period to effect a nal but too short to permit release of the armature of any slow-to-release relay 36.

In each station equipment, four code-signal members such as H are provided to operate're spectively four sets of contact springs in the man.- ner of contacts I6 and I1, Fig. 3, and as described in Patent 1,904,164, cited, illustrated at 2| 22, 23, and 24 for each station.

Referring now to Fig. 1, the line circuit 3| extends in series through stations A, C, and E, the letter identifying the station serving also to identify the calling code-signal in response to which the station may be qualified for communication. At each station the line circuit 3| passes through a keyboard transmitter 32, a line relay 34 which may be either polar or neutral, and a pair of associated manually operable break keys I8 and I9. Station equipment responsive to the line relay 34 includes printer magnet 35 symbolizing a complete telegraphic printing equipment for operating printing types to record received bode signals and also eiiective by means of a plurality of apparatus as illustrated in. Fig. 3 to operate contact devices 2|, 22, 23,and 24, in response to selective code signals. In the case of contact device 2| the controlling codesignals are variant for the several stations respectively and constitute the variant calling signals for the several stations individually. Contact devices 22 are responsive through code members alike at all stations forming a group of stations which are to be called jointly as a group by a single code signal. Such a group may include all stations of a system. Contact devices 23 are controlled by code members alike at all sta tions andare responsive to a stop code signal Z, while contact devices 24 are controlled'by other code members alike at all stations and are responsive to a lookout code signal Y.

There are also controlled by line relay 34 and by the contact members 2| to 24 inclusive slow-to-release relay 36, a motor control relay 31, a call responsive relay 36 and a busy signal relay 39, together with a driving motor 4 i, a white signal lamp 42 and a red signal lamp 43, the white lamp 42 constituting a visual signal indicating, whenilluminated, that the station is qualified for telegraphic reception and transmission and the red lamp 43 indicating, when illuminated, that line 3| is held in a completed communicative con dition.

There is also at each station the answer-back magnet 6 with armature pivoted at and connected mechanically to the keyboard ball I and there is provided at eachstation a single striker 4 upon a key lever 3 of the keyboard transmitter 32, the striker 4 being fixed upon variant key levers at the several stations preferably as folcircuit of the key and "break sig-' lows: At station A upon key lever B, at station 0 upon key lever D, at station E upon key lever F, and so on, the alphabet being exhausted when 12 stations have been designated alphabetically, reserving Y and Z for lockout and stop conditions as noted above. Optionally, fewer or a single character-code signal may be utilized for answering, thus amplifying the directory possibilities of the alphabet to accommodate a greater number of stations.

At" an appointed monitoring station if desired, a manual key 48 is connected to grounded battery and to motor 4|, and at each'station a shunt path 49 around transmitter 32 and keys 8, l9 may be closed by contacts in relay 3!! or opened by contacts in relay 38 or by contacts in key 48.

Electrical connections of the recited parts will be understood from circuit tracings embodied in description of operation below.

Operation of the system is as follows in which it will be assumed that station A is calling station C for communication exclusive of station E.

An operator at station A first operates the motor controlskey Hi. This deenergizes all line relays 34 and eifects release of armatures of all slow-to-release relays 36 at all stations with resultant energization of motor control relays 31 at all stations, each relay 31 through its righthand-armature setting up its own holding circuit through contacts of devices 24 and 23 to grounded battery 40, and each relay 3'! through its lefthand armature also sett' g up the condition of starting and continuing operation of all motors 4| at all stations and of illuminating the white lamps 42 at all stations. The printing telegraph receivers of which magnet 35 constitutes a part are now in condition to receive message signals. Automatic reclosing of key l9 reenergizes all relays 36. v

The operator at station A next transmits by keyboard transmitter 32 the call letter A for such station which operates contact device 2| at station A but not at any other station because only at station A'is the code lever N, Fig. 3, cut for the code signal A, but the character A is printed at all stations in response to the calling code signal over the line 3|. Responsive to operation of contact device 2| at station A, the call-responsive relay 38 thereat is energized through its righthand winding and forms its holding circuit through its left-hand winding, its own contact and grounded battery 44. Answer-back magnet 6 at station A also is energized momentarily overa circuit through left armature and back contact of relay 39 and contact device 2| to battery 40. Magnet 6 attracts its armature momentarily and the bail I through striker 4 depresses the key lever 3 momentarily with the same effect as manually striking the key B. Responsively, the keyboard transmitter 32 transmits the code signal B upon the line 3| thus completing a recording at all stations of AB.

Operator at station A now operates key of the keyboard thus transmitting the code signal for station C to which the contact device 2| at station C responds but not at any other station because only at station C is therefqund a code lever cut for code signal C, but the character C is printed at all stations, and in response to contact device 2| at station C the call signal relay 38 at station C responds and forms its holding circuit through relay 36 at station C and answer-back magnet 6 responds and operates a key lever of the keyboard at station 0 but in thisinstance it is key lever D resulting in the operation of keyboard transmitter 32 at station C to transmit the code signal D upon line circuit 3| resulting in printing D at all stations and thus completing a recording of ABCD at all stations. I I

Operator at station A having qualified stations A and C as desired, now disqualifles all other stations by striking keyboard lever Y which transmits upon line 3| a code signal for Y which prints Y at all stations and all stations the contact device 24 producing four results. First, atxall stations relay 39 is energized over an obvious circuit through the upper contact of device 24 and forms its holding circuit through contacts of relay 36 to grounded battery 44. Second, the holding circuit described above for relay 3'! at non-qualified station E is broken by contact device 24, the relay is deenergized and releases its armature to stop its motor M and to extinguish its white lamp 42. Third, energized busy relays 39 also illuminate the red busy lamps 43 at all stations whether a station has been selected or excluded. Fourth, at each excluded station, right-hand armature of energized busy relay 39 and right-hand armatureoi unenergized call-signal relay 38 close ashortcircuiting shunt 49 around transmitter 32 and keys |8.and l9 rendering those instrumentalities irieifective even if manually operated. However, at selected and qualified stations A and C while the contact device 24 breaks the original holding circuit of motor control relay 31, the relay 31 is not deenergized at this time because' a further holding circuit for this relay has been set up and now continues through contacts of relay 3! and contacts of energized call-signal relay'38 to battery. It results, therefore, that motors 4| continue operation at the qualified stations A and C and that motors 4| are. stopped at all unqualified stations? including station E and any other station connected to line conductor 3|. The code signals may be selected variantly; for instance, code signal for word space or line feed may be substituted for Y above and carriage return for Z below, and have some advantages. At each station there now has been printed pen the recording surface ,of the telegraphic printer the record ABCDY'indicating that sta tion A has been calling, that station C has been called and has responded, and that all other stations have been excluded. The white lamp and the red lamp are glowing at each qualified station while the red lampalone is glowing at all excluded stations. The excludedstations thus are provided with knowledge of the identity of the stations which are using the line circuit 3|. Favored stations or monitor stations have a further supervisory function as illustrated at station A which may be exercised by operation of manual key 48. I An operator at an excluded monitoring station desiring to dispatch a message over line 3| may close key 48 at such station, thereby energizing the motor 4| at that station over an obvious circuit. Rotation of the motor renders eilectively operative the recorder 35, the keyboard transmitter 32, and the manual keys l8 and IS. The operator at the excluded monitor station now may judge of the relative importance of the proposed message over the probable importance of the message being currently transmitted between or among the prior communicating stations and which now is being recorded at the conditionally qualified monitor station and if the operator so which operates at above in connection with illustration desires may interrupt the instant communication by operating key l9 to restart all stopped motors and then may set up any desired connection.

The object of break key I8 is to enable-- any duly qualified communicating station. or monitor station to interrupt operation of the line circuit long enough, to indicate a request to the then transmitting station to desist from transmission, but not long enough to releasethe armature of any relay 36. I 10 Assuming that the communication as set up above between stations A and C is not interrupted, then at the close of the communication period'either station A or C may operate the motor controlkey i9 which will deenergize and release all slow-to-release relays 36 at all sta-- tions and will interrupt the holding circuits of all operated relays 38 and 39 at all stations. Release of relay 39, will interrupt the energizing circuits of all busy signal lamps 43. Deenergization of relays 36 at excluded stations will reenergize motor control relays 3i and will restart motors M at those stations. Accordingly, all motors will be operating at all stations. The operator then may transmit a stop code signal Z which will print Z at all stations, operate contact device 23 at all stations to interrupt the holding circuit of motor'control-relay 311 at all stations'thus stopping all motors, extinguishing all white lamps 42, and restoring allapparatus to its normal condition of idleness and readiness for further service.

At every station there will have been recorded complete information of the connection in' the form of .ABCDYZ, except that at connected stations the message record. will be included between Y and Z. I

The present invention having been described of a specific embodiment thereof now will be considered more 40 generally and will be definitely pointed out in I the claims without limitation to the specific form used above for illustration.

What is claimed is: I I

1. The method of operating a telegraphic answer-back system for a telepgraph system wherein a plurality of stations are connected to a single line circuit which comprises, assigning calling signals variant for every station of the system whicl'i connect the station to the signaling circuit, assigning answer-back signals variant for every station, and transmitting from every station in response to receipt of the calling signal of that station, the answer-back signal of that station which is variant from every calling signal.

2. The method of operating a telegraphic answer-back system for a telegraph system wherein a plurality of stations are connected to a single line circuit which comprises, assigning calling signals variant for every station of the system which connect the station to the signaling circuit, as- I signing answer-back signals for all stations and transmitting from every station in response to receipt of the calling signal of that station, the answer-back signal assigned to that-station which is variant from each calling signal.

3. The method of operating a-telegraphic an-- swer-back system for a telegraph'system wherein a plurality of stations are connected to a single line circuit which comprises, assigning calling signals variant for every station of the system which connect the station to the signaling circuit, assigning at least one answer=back signal, and transmitting from response to receipt a station in oithe calling signal of that station, an answer- 76 back signal diflerent the station.

4. The method of operating a telegraphic system which comprises, transmitting calling code signals for each station, transmitting answer-back code signals from each called station, the number of called stations being less than the total number of stations, transmitting a change over code signal indicating the termination of activity of station selection and the beginning of tercommunication, transmitting a communication terminating code signal, and recording all said code signals at all stations. A v

5. The method of operating a telegraphic system which comprises, transmitting calling code signals for each station to be connected, transmitting answer-back code signals from each called station, the number of called stations being less than the total number of stations, transmitting a code signal indicating disconnection, and recording all said code signals at all stations.

' 6. Mechanism for operating an answer-back system in which the answer-back signal is a code signal to be transmitted in response to operation of a single key lever of a telegraphic keyboard transmitter, comprising a telegraph station, a keyboard transmitter, a key lever in said keyboard ,transmitter, an answer-back magnet and arma ture, said armature positioned to engage and operate said key lever in response to energization of said magnet, and means to energize said magnet in response to receipt of a predetermined calling code signal which identifies said station.

7. Mechanism for operating an answer-back system comprising a station, a keyboard transmit-- ter at said station, a key lever in said transmitter to control said transmiter to transmit an answerback signal, a magnet and armature, means integrallynnited with said armature to engage and operate said key lever when said armature is operated, and-means responsive to a received calling code signal identifying said station for operating said magnet.

8. In a selective and intercommunicative telegraph system, a plurality of telegraphic stations, means at each station to transmit an answer-back message in response to receipt of code signals representing the calling signals of the station, and means at each station responsive to a received code signal to render said answer-back means non-responsive. 4

9. In a selective and intercommunicative telegraph system, means to establish in said system a station selecting and answer-back condition means to transmit an answer-back message in response to a selection of a station, and means to terminate said station selection and answer-back condition.

10. In a selective and intercommunicative telegraph system, a plurality ,of telegraphic stations, means at each of said stations to transmit an answer-back message upon seizure of the station for communication, and means at each station reirom the calling signal of sponsive to a received code signal to render said answer-back means, non-responsive.

11. In a motor control system, a motor, a control relay for said motor, a line circuit, a key having contacts in said line circuit to which contacts said control relay is responsive, a shunt for said contacts of said key to render said contacts ineffective, a relay having contacts included in said shunt to close said shunt, and a'call-responsive relay having contacts included in said shunt to open said shunt.

12. In a motor control system, a telegraph line activity 01. in-

circuit, a telegraphic recording and transmitting equipment included in said line circuit, a motor mechanically associated with said telegraphic equipment, remotely controlled means eifective through said line circuit for energizing and deenergizing said motor and for shunting said transmitting equipment, and wholly local means for energizing and deenergiz'ing said motor and for removing the shunt of said transmitting equipment.

13. In a motor control system, a telegraphic line circuit, a plurality-of telegraphic recording and transmitting equipments included in said line circuit, a plurality of motors one mechanically associated with each of said telegraphic equipments, remotely controllable starting and stop ping means for each of said motors, a plurality of keys, one at each of said telegraphic equipments for remotely controlling said starting and stopping means, remotely controllable means for disabling a desired one of said keys, and wholly local means associated with one of said equipments and with said disabled one of said keys for starting said motor associated with said disabled one of said keys.

14. In a motor control system, a line, a plurality of motor driven printing telegraph equipments on said line responsive to permutation code signals of equal length and having normally inert motors, and first automatic key manually operable to transmit on said line a prolonged non-permutation signal longer than one of said permutation code signals, a second automatic key manually operable to transmit on said line a more greatly prolonged non-permutation code signal, and motor controlling'means responsive to said more greatly prolonged signaJ, said printing telegraph equipment being unresponsive selectively to said prolonged non-permutation signal because it is too long and said motor controlling means being unresponsive to said prolonged non-permutation signal because it is too short.

15. In a telegraphic station selecting system. a line circuit, a plurality of stations on said line circuit, printing telegraphic receivers one at each station each including a motor driven selector with driving motor therefor normally inert, means responsive to a non-permutation motor-control signal of a predetermined minimum duration over said line circuit Iorstarting said motors at all stations, means responsive to permutation code signals of uniform duration for operating said receiver, and a mechanically regulated manually operable break key for transmitting a non-permutation break signal of predetermined duration longer than one of said permutation code signals and shorter than said non-permutation motor-control signal.

16. In a multi-station telegraph system, normally inert motors and motor control relays one at each station, means to energize all said relays to start all said motors and to continue each of said motors operating while its associated relay remains energized, means for deeneigizing all of said relays, and call-responsive means one at each station responsive to predetermined variant calling code signals one for each station, each i said call-responsive means adapted to condition at each station for said relays,

ated relay remains energized,'holding circuits one means to interrupt all said holding, circuits, and means one at each station responsive to a predetermined code signal and each adapted to form a further holding circuit for the associated one ofsaid relays. 18. In a multi-station ..telegraph system, a recording receiver, a motor driven permutation selector included inv said receiver having a nor-. mally inert motor, a motor/control relay controlling said motor to operate while saidrelay re- 1 mains energized, remotely controlled means for ablingall said "ing a station for communication,

energizing saicL relay to operate said motor and to mm a provisional holding circuit for said relay, means responsive to said selector to form a further holding circuit for said relay, and further means responsive to said selector to inter-" rupt said provisional holding circuit.

19. In a multi-station telegraph system, a line, a plurality of stations connected to. said line, permutation code selectors one at each' of said stations, means responsive to said selectors when operating in response to permutation code signals for selecting a station for communication, means responsive to said selectors when operating in response to permutation code signals for disfirst mentioned means, means responsive to said selectors when operating in response to permutation code signals for restoring said station to normal condition, and means for recording at all stations all of said permutation code signals above mentioned. v

20. In a multi-station telegraphic system, a line, a plurality of stations connected to said line, permutation code selectors one at each of 'said stations, means operable by said selectors in response to permutation code signals for selectmeans responsive to said selectors for transmitting an answerback permutation code signal, means responsive to said selectors for disabling said station selecting equipment, means operable by said selectors in response to permutation code signals for restoring all apparatus to normal, and means operable by said selectors for recording at all stations all of said permutation code signals.

21. In a signaling system, a telegraph line circult normally in non-communicative condition, a plurality of telegraph apparatus sets associated with ,said circuit andnormally inoperative, selective means to'render said sets individually operative, means to render said line circuit in com- .municative condition, a system of visual signals at one of said stations, means to display a signal in .said system when said line circuit is in communicative condition, and means to display a dii-,

, ierent signal in said system when said one of said stations isindividually operative.

22. The method of operating a telegraphic system including a single channel of communication and a plurality of stations thereon which comprises, transmitting over said channel to each station calling code signals for each, station, transmitting answer-back code signals from each called station, transmitting a change-over code tionv of a single nication terminating code signal, and recording all said code signals at one station.

23. The method of operating a telegraphic system including a single. channel of communication and a plurality of stations thereon which comprises, transmitting calling code signals for each station to be connected telegraphically to -said channel, transmitting answer-back code signals from each called station, transmitting a code ,signal indicating disconnection, and recording all said code signals at one stations 24. Mechanism for operating an answer-back system in which the answer-back signal is a code signal to be transmitted in response to operakey lever of a telegraphic keyboard transmitter, a telegraphic station including a keyboard transmitter, a key lever in said keyboard transmitter, an answer-back magnetand armature, mechanical means integral with said armature and tegral with said keyboard key lever, said mechanical means and said further mechanical means mutually engageable for operating said key lever in response to energization of said mag-, net, and means to seize a station for communication and to, energize said magnet in response to seizure of said telegraphic station for communication.

25. Mechanism for operating an answer-back system comprising a telegraphic station, a keyboard transmitter at said station, a key lever in said transmitter transmit an answer-back signal, a magnet and armature, said armature positioned to mechanically engage said key lever when operated, and means for operating said armature upon seizure of said station for communication. I 26. In a motor control system, a telegraph line circuit, a telegraphic-reeording selector included in said line circuit, a motor mechanically associated with said telegraphic selector, remotely controlled means effective through said line circuit for energizing said motor, remotely controlled means eflective through said selector for deenergizing said motor, and wholly local means for energizing and deenerglzing said motor.

27. In a multi-station telegraphic system, a line, a plurality of stations connected to said line, permutation code selectors one at each 0! said stations, means operable by said selectors in response to permutation code signals for selecting a station for communication, means operative upon station selection for transmitting an answer-back permutation code signal, means responsive to said selectors for disabling said station selecting equipment, means operable by said selectors in response to permutation code signals for restoring all apparatus to normal, and means operable by said selectors for recording at all stations all of said permutation code signals.

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to control said transmitter tofurther mechanical means in- 

